Ultra-high-density mapping allows very accurate characterization of mechanisms involved in AT. Some complex patterns may involve AAD which is longer than the tachycardia cycle length (TCL) which makes maps difficult to interpret. Prevalence and characteristics of such ATs are unknown.

Editor-in-Chief
David J. Wilber, MD, FACC

CME Editor
Smit Vasaiwala, MD

Author
Smit Vasaiwala, MD

CME Information
Target Audience
JACC Journal CME is intended for physicians who treat patients with cardiovascular disease.

Important Dates
Date of Release: August 19, 2019
Term of Approval/Date of CME/MOC/ECME Expiration: August 18, 2020

Learner Objectives
After reading this article the reader should be able to:

• Discuss the fundamentals of mapping of atrial tachycardia.
• Discuss the role of ultra–high-density mapping for atrial tachycardias.  
• Detect and correctly diagnose atrial tachycardia with an atrial activation duration larger than the tachycardia cycle length. 

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